/* -*- coding: utf-8 -*-
 *
 * 2492.cc:  No.2492 Knapsack Problem? - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int n, w;
  scanf("%d%d", &n, &w);

  int maxv = -1;
  for (int i = 0; i < n; i++) {
    int vi, wi;
    scanf("%d%d", &vi, &wi);
    if (wi <= w) maxv = max(maxv, vi);
  }

  printf("%d\n", maxv);

  return 0;
}